PLANT DISEASES CCA TRAINING - University of Delaware004).pdf · 2020-01-29 · plant diseases cca...
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PLANT DISEASES PLANT DISEASES CCA TRAINING CCA TRAINING BOB MULROONEY BOB MULROONEY EXTENSION PLANT PATHOLOGIST EXTENSION PLANT PATHOLOGIST UNIVERSITY OF DELAWARE UNIVERSITY OF DELAWARE
Transcript of PLANT DISEASES CCA TRAINING - University of Delaware004).pdf · 2020-01-29 · plant diseases cca...
PLANT DISEASESPLANT DISEASESCCA TRAININGCCA TRAINING
BOB MULROONEYBOB MULROONEYEXTENSION PLANT PATHOLOGISTEXTENSION PLANT PATHOLOGIST
UNIVERSITY OF DELAWAREUNIVERSITY OF DELAWARE
COMPETENCY AREA 2COMPETENCY AREA 2
Management of Plant DiseasesManagement of Plant Diseases
Disease IdentificationDisease Identification
SymptomsSymptomsSignsSigns
SYMPTOMSSYMPTOMS
External and internal reactions or External and internal reactions or alterations of a plant as a result alterations of a plant as a result of a diseaseof a disease
Disease symptoms
SIGNSSIGNS
The pathogen (disease The pathogen (disease causing agent) or its parts or causing agent) or its parts or products seen on a host plantproducts seen on a host plant
Disease signsDisease signs
CLASSIFY DISEASES BY CLASSIFY DISEASES BY PATHOGENPATHOGEN
FUNGUSFUNGUSBACTERIABACTERIAVIRUSVIRUSNEMATODENEMATODE
EXAMPLESEXAMPLES
WHEATWHEAT–– TAKETAKE--ALL caused by a ALL caused by a FUNGUSFUNGUS–– BARLEY YELLOW DWARF caused by BARLEY YELLOW DWARF caused by
a a VIRUSVIRUS
KNOW CONDITIONS THAT KNOW CONDITIONS THAT FAVOR DISEASE FAVOR DISEASE
DEVELOPMENT FOR EACH DEVELOPMENT FOR EACH DISEASEDISEASE
CLIMATIC CONDTIONS CLIMATIC CONDTIONS CROPPING PRACTICESCROPPING PRACTICES
DETERMINE CONTROL DETERMINE CONTROL MEASURES FOR EACH MEASURES FOR EACH
DISEASEDISEASE
CULTURALCULTURALCHEMICALCHEMICAL
CULTURAL CONTROLSCULTURAL CONTROLS
ROTATIONROTATIONVARIETY (HYBRID) SELECTIONVARIETY (HYBRID) SELECTIONPLANTING DATEPLANTING DATEFERTILITY MANAGEMENTFERTILITY MANAGEMENTTILLAGETILLAGEWEED CONTROLWEED CONTROL
DISEASE CONTROLDISEASE CONTROL
Some diseases may require a Some diseases may require a number of cultural controls or number of cultural controls or combination of cultural and combination of cultural and chemical controls.chemical controls.
CORN DISEASESCORN DISEASES
Lesion nematodeLesion nematodeSymptom/SignSymptom/Sign
Lesions on rootsLesions on rootsstunting of corn with uneven distribution in stunting of corn with uneven distribution in fieldfield
Lesion NematodeLesion Nematode
Lesion nematodeLesion nematodeControl MethodsControl Methods
Rotation but few nonRotation but few non--hosts grown.hosts grown.Granular insecticide Granular insecticide egeg. Counter 15G. Counter 15G
Maize dwarf mosaic (virus)Maize dwarf mosaic (virus)Symptom/SignSymptom/Sign
Yellow stripes between veins on youngest Yellow stripes between veins on youngest leavesleavesStuntingStuntingShortened internodesShortened internodesSporadic distribution in fieldSporadic distribution in field
Maize Dwarf MosaicMaize Dwarf Mosaic
Maize dwarf mosaic (virus) Maize dwarf mosaic (virus) Conditions Conditions favoring developmentfavoring development
Johnsongrass alternate hostJohnsongrass alternate hostAphids transmit to cornAphids transmit to corn
Maize dwarf mosaic (virus)Maize dwarf mosaic (virus)Control MethodsControl Methods
Resistant varietyResistant varietyControl JohnsongrassControl Johnsongrass
Maize chlorotic dwarf (virus)Maize chlorotic dwarf (virus)Symptom/SignSymptom/Sign
Chlorosis (yellowing) severe on young Chlorosis (yellowing) severe on young leavesleavesSome reddeningSome reddeningSevere stuntingSevere stunting
Maize chlorotic dwarf (virus)Maize chlorotic dwarf (virus)
Maize chlorotic dwarf (virus)Maize chlorotic dwarf (virus)Conditions favoring developmentConditions favoring development
Johnsongrass alternate hostJohnsongrass alternate hostLeafhopper transmits to cornLeafhopper transmits to corn
Maize chlorotic dwarf (virus)Maize chlorotic dwarf (virus)Control MethodsControl Methods
Resistant varietyResistant varietyControl JohnsongrassControl Johnsongrass
Northern corn leaf blight (fungus)Northern corn leaf blight (fungus)Symptom/SignSymptom/Sign
Gray green elliptical (cigarGray green elliptical (cigar--shaped) spots, 2shaped) spots, 2--6 inches long on hybrids with no resistance.6 inches long on hybrids with no resistance.Lesion size can be affected by hybrid.Lesion size can be affected by hybrid.Can be confused sometimes with Stewart’s Can be confused sometimes with Stewart’s wilt if certain resistance genes are present.wilt if certain resistance genes are present.
Northern Corn Leaf Blight (fungus)Northern Corn Leaf Blight (fungus)
Northern corn leaf blight (fungus)Northern corn leaf blight (fungus)Conditions favoring developmentConditions favoring development
Moderate temperatureModerate temperature----6565--85 F85 FLong dew periodsLong dew periodsOverwinters on plant debrisOverwinters on plant debrisWindborneWindborne
Northern corn leaf blight (fungus)Northern corn leaf blight (fungus)Control MethodsControl Methods
Resistant hybridsResistant hybridsCrop rotationCrop rotationTillageTillage
Southern corn leaf blight (fungus)Southern corn leaf blight (fungus)Symptom/SignSymptom/Sign
Spots on leaf smaller and more numerous Spots on leaf smaller and more numerous than Northern corn leaf blightthan Northern corn leaf blightSpots vary in size and shape due to the Spots vary in size and shape due to the genetic background of the hybrid.genetic background of the hybrid.Common race “O” produces tan, elongated Common race “O” produces tan, elongated spots between the veins that have limited spots between the veins that have limited parallel margins and possibly buff to brown parallel margins and possibly buff to brown borders.borders.
Southern Corn Leaf Blight (fungus)Southern Corn Leaf Blight (fungus)
Southern corn leaf blight (fungus)Southern corn leaf blight (fungus)Conditions favoring developmentConditions favoring development
Warmer temperatureWarmer temperature----6868--90 F90 FHigh humidityHigh humidityOverwinters on plant debrisOverwinters on plant debrisWindborneWindborneSplashed by waterSplashed by water
Southern corn leaf blight (fungus)Southern corn leaf blight (fungus)Control MethodsControl Methods
Resistant hybridsResistant hybridsCrop rotationCrop rotationTillageTillage
Carbonum(Northern corn) Leaf Spot Carbonum(Northern corn) Leaf Spot (fungus)(fungus)
Symptom/SignSymptom/SignRace 3 produces very narrow spots often Race 3 produces very narrow spots often resembling “beads on a string”. resembling “beads on a string”. Lesion (spot) type varies with the hybridLesion (spot) type varies with the hybridOften spreads after leaf tissue maturesOften spreads after leaf tissue matures
Carbonum Leaf SpotCarbonum Leaf Spot
Carbonum(Northern corn) Leaf SpotCarbonum(Northern corn) Leaf SpotConditions favoring developmentConditions favoring development
Moderate temperatures and high humidityModerate temperatures and high humiditySpores are abundantly produced on old spots on Spores are abundantly produced on old spots on mature leavesmature leavesMinor importance, small impact on yield.Minor importance, small impact on yield.
Carbonum leaf blight (fungus)Carbonum leaf blight (fungus)Control MethodsControl Methods
Resistant hybridsResistant hybridsCrop rotationCrop rotationTillageTillage
Gray leaf spot (fungus)Gray leaf spot (fungus)Symptom/SignSymptom/Sign
Rectangular lesions with sharp parallel edges, Rectangular lesions with sharp parallel edges, restricted by veins with yellow marginrestricted by veins with yellow marginWindow pane look, and old lesions are opaque.Window pane look, and old lesions are opaque.Early lesions are small necrotic spots with Early lesions are small necrotic spots with chlorotic halos.chlorotic halos.Often symptoms are worse along the edges of Often symptoms are worse along the edges of fieldsfields
Gray Leaf Spot (fungus)Gray Leaf Spot (fungus)
Gray leaf spot (fungus)Gray leaf spot (fungus)Conditions favoring developmentConditions favoring development
High humidityHigh humidityNear water waysNear water waysOverwinters in residueOverwinters in residueReduced tillage or noReduced tillage or no--till till
Gray leaf spot (fungus)Gray leaf spot (fungus)Control MethodsControl Methods
Resistant hybridsResistant hybridsTillage is recommended but is questionable where Tillage is recommended but is questionable where the disease is well established.the disease is well established.RotationRotation
Common Rust (fungus)Common Rust (fungus)Symptom/SignSymptom/Sign
Golden brown to cinnamon brown pustules on Golden brown to cinnamon brown pustules on both sides of the leaf.both sides of the leaf.
Common Rust (fungus)Common Rust (fungus)
RustRustConditions favoring developmentConditions favoring development
Spores are wind blown from the south.Spores are wind blown from the south.Moderate temperatures (61Moderate temperatures (61--80) and high humidity80) and high humidityInfections often occur in the whorl where Infections often occur in the whorl where moisture and humidity are highmoisture and humidity are high
RustRustControl MethodsControl Methods
Resistant hybridsResistant hybrids
Fusarium stalk rot (fungus)Fusarium stalk rot (fungus)Symptom/SignSymptom/Sign
Cottony white mat of fungus at base of plant Cottony white mat of fungus at base of plant or at internodesor at internodesSoft rotted stalkSoft rotted stalkRed discoloration inside of stalkRed discoloration inside of stalkLodgingLodgingYield lossYield loss
Fusarium Stalk RotFusarium Stalk Rot
Fusarium stalk rot (fungus)Fusarium stalk rot (fungus)Conditions favoring developmentConditions favoring development
Reduced tillage or noReduced tillage or no--till till Fungus overwinters in crop residueFungus overwinters in crop residueWarm, wet conditionsWarm, wet conditionsCan enter through wounds or directly ( corn Can enter through wounds or directly ( corn borer interaction)borer interaction)Same organism causing scab in cerealsSame organism causing scab in cereals
Fusarium stalk rot (fungus)Fusarium stalk rot (fungus)Control MethodsControl Methods
Hybrid selectionHybrid selectionTillageTillageProper fertilityProper fertilityRotationRotationEarly harvestEarly harvest
Fusarium ear rot (fungus)Fusarium ear rot (fungus)Symptom/SignSymptom/Sign
White fungus growing on kernelsWhite fungus growing on kernelsPink discolorationPink discoloration“Starburst” symptom on infected kernels“Starburst” symptom on infected kernels
Diplodia Fusarium Giberella
‘Starburst pattern’
Fusarium
Fusarium Ear RotFusarium Ear Rot
Fusarium ear rot (fungus)Fusarium ear rot (fungus)Conditions favoring developmentConditions favoring development
Reduced or noReduced or no--till till Fungus overwinters in crop residueFungus overwinters in crop residueWarm, wet conditionsWarm, wet conditionsInsect damage to earInsect damage to earCan produce Can produce mycotoxinmycotoxin ““fumonisonfumonison””
Fusarium ear rot (fungus)Fusarium ear rot (fungus)Control MethodsControl Methods
TillageTillageProper fertilityProper fertilityRotationRotationEarly harvestEarly harvest
SOYBEAN DISEASESSOYBEAN DISEASES
Damping OffDamping OffSymptom/SignSymptom/Sign
Seedlings fail to emerge or emerge then dieSeedlings fail to emerge or emerge then dieSeed or root is brown and decayedSeed or root is brown and decayed
Damping OffDamping OffConditions favoring developmentConditions favoring development
Cool, damp conditionsCool, damp conditions
Pythium
Rhizoctonia
Damping OffDamping Off
Damping OffDamping OffControl MethodsControl Methods
Seed treatment fungicidesSeed treatment fungicidesLater planting dateLater planting dateRotationRotation
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Symptom/SignSymptom/Sign
Poor growth Poor growth WiltingWiltingBrown discoloration on stemBrown discoloration on stemRotted rootsRotted roots
Phytophthora Root RotPhytophthora Root Rot
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Conditions favoring developmentConditions favoring development
Poorly drained areasPoorly drained areasHeavy soilsHeavy soilsFloodingFlooding
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Control MethodsControl Methods
Resistant varietyResistant varietySeed treatments using Apron, Apron Seed treatments using Apron, Apron XL, or Allegiance control the dampingXL, or Allegiance control the damping--off stage.off stage.
Rhizoctonia root rot (fungus)Rhizoctonia root rot (fungus)Symptom/SignSymptom/Sign
Seedlings emerge and dieSeedlings emerge and dieBrown, redBrown, red--brown, or red sunken lesion on brown, or red sunken lesion on roots or base of the seedling stem.roots or base of the seedling stem.
Rhizoctonia root rot (fungus)Rhizoctonia root rot (fungus)Conditions favoring developmentConditions favoring development
Cool, damp conditionsCool, damp conditionsFertility, soil conditions and the amount of Fertility, soil conditions and the amount of fungus in the soil can all influence the fungus in the soil can all influence the degree of infection. degree of infection.
Rhizoctonia root rot (fungus)Rhizoctonia root rot (fungus)Control MethodsControl Methods
Fungicide seed treatmentsFungicide seed treatmentsLater planting dateLater planting date
SeptoriaSeptoria leaf spot leaf spot (Brown spot)(Brown spot)Symptom/SignSymptom/Sign
Irregular dark brown spots Irregular dark brown spots onon unifoliateunifoliate leaves leaves progressing toprogressing to trifoliatestrifoliateslater in the season.later in the season.InfectedInfected unifoliateunifoliate leaves leaves turn brown and dropturn brown and dropBlack fruiting bodies Black fruiting bodies ((pycnidiapycnidia) of the fungus ) of the fungus form in old spots.form in old spots.
SeptoriaSeptoria leaf spotleaf spotConditions favoring developmentConditions favoring development
Fungus overwinters on old infected plant debrisFungus overwinters on old infected plant debrisUnifoliate Unifoliate infection provides infection provides inoculuminoculum for later for later infectioninfectionWarm, wet weather conditions especially later in Warm, wet weather conditions especially later in the season influences brown spot in the canopy.the season influences brown spot in the canopy.
SeptoriaSeptoria leaf spotleaf spot
Control MethodsControl MethodsRotationRotationPlant less susceptible varietiesPlant less susceptible varietiesPlow under crop residuesPlow under crop residues
Charcoal rotCharcoal rotSymptom/SignSymptom/Sign
Usually after midseason, plants appear stunted in Usually after midseason, plants appear stunted in irregular areas of the field.irregular areas of the field.Leaves may turn yellow and wiltLeaves may turn yellow and wiltLower stem and taproot develop a gray to silvery Lower stem and taproot develop a gray to silvery discolorationdiscolorationMicrosclerotia Microsclerotia develop in epidermis on root and develop in epidermis on root and lower stem and inside pith resembling charcoal lower stem and inside pith resembling charcoal dustdust
Charcoal RotCharcoal Rot
Charcoal rotCharcoal rotConditions favoring developmentConditions favoring development
Low soil fertilityLow soil fertilityContinuous cropping of soybeans.Continuous cropping of soybeans.Low soil moisture and hot temperatures Low soil moisture and hot temperatures increase disease severity.increase disease severity.
Charcoal rotCharcoal rotControl MethodsControl Methods
Plant later maturing varieties late group IV’s and Plant later maturing varieties late group IV’s and group V’s.group V’s.Rotate with small grains, corn and sorghum for at Rotate with small grains, corn and sorghum for at least 3 years in severely infected fields.least 3 years in severely infected fields.Do not Do not overplantoverplant, causes seedling stress, causes seedling stressGood fertility practicesGood fertility practices
SclerotiniaSclerotinia white mold (fungus)white mold (fungus)Symptom/SignSymptom/Sign
Wilting and death of the upper leaves of the plants Wilting and death of the upper leaves of the plants during early pod developmentduring early pod developmentOften occurs in patches in low areasOften occurs in patches in low areasWhite mat of fungus on stem at nodes often seenWhite mat of fungus on stem at nodes often seenStem lesions often Stem lesions often girldle girldle the stem and the the stem and the uper uper portions die and produce no pods.portions die and produce no pods.Large Large sclerotiasclerotia on stem and sometimes in pithon stem and sometimes in pith
Sclerotinia Sclerotinia White MoldWhite Mold
SclerotiniaSclerotinia white mold (fungus)white mold (fungus)Conditions favoring developmentConditions favoring development
Cool, wet conditions that favor germination Cool, wet conditions that favor germination of of sclerotia sclerotia within the upper 2 inches of soil.within the upper 2 inches of soil.Narrow row spacingNarrow row spacingDense canopy structureDense canopy structureFields with history of white mold on crops Fields with history of white mold on crops of peas, beans, and soybeanof peas, beans, and soybean
SclerotiniaSclerotinia white mold (fungus)white mold (fungus)Control MethodsControl Methods
Avoid planting soybeans after other Avoid planting soybeans after other susceptible crops such a peas, snap and lima susceptible crops such a peas, snap and lima beans, and sunflowers.beans, and sunflowers.Choose varieties that are shorter, more openChoose varieties that are shorter, more open
Pod and stem blight (fungus)Pod and stem blight (fungus)Symptom/SignSymptom/Sign
Rows of black fruiting bodies (Rows of black fruiting bodies (pycnidiapycnidia) on ) on stems, petioles and pods late in season stems, petioles and pods late in season Infected seeds are decayed which leads to Infected seeds are decayed which leads to direct yield lossdirect yield loss
Pod and Stem BlightPod and Stem Blight
Pod and stem blight (fungus)Pod and stem blight (fungus)Conditions favoring developmentConditions favoring development
Disease of senescing soybeansDisease of senescing soybeansSeed infection favored by delayed harvestSeed infection favored by delayed harvestWarm, rainy weather during pod Warm, rainy weather during pod development through maturity.development through maturity.Low potash levels favor more seed Low potash levels favor more seed infection.infection.
Pod and stem blight (fungus)Pod and stem blight (fungus)Control MethodsControl Methods
RotationRotationTillageTillageResistant varietyResistant varietyMaintain high level of potash fertilityMaintain high level of potash fertility
AnthracnoseAnthracnoseSymptom/SignSymptom/Sign
Often appears in early reproductive stages on Often appears in early reproductive stages on stems, petioles and pods as an irregularly shaped stems, petioles and pods as an irregularly shaped brown areas. Often resembles pod and stem brown areas. Often resembles pod and stem blight.blight.Fruiting bodies of the fungus are randomly Fruiting bodies of the fungus are randomly scattered on infected plants tissues and produce scattered on infected plants tissues and produce black spines called setae that can be seen.black spines called setae that can be seen.Can produce cankers on petioles and stems Can produce cankers on petioles and stems causing severe defoliation.causing severe defoliation.
AnthracnoseAnthracnose
AnthracnoseAnthracnoseConditions favoring developmentConditions favoring development
Overwinters on debris and can infect seed.Overwinters on debris and can infect seed.Moist, warm weather during reproductive stages.Moist, warm weather during reproductive stages.Plants are most susceptible from bloom to pod fillPlants are most susceptible from bloom to pod fillNeed wet periods of 12 hours or more for Need wet periods of 12 hours or more for infecton infecton to occur. to occur.
AnthracnoseAnthracnoseControl MethodsControl Methods
Plant disease free seedPlant disease free seedPlow down old soybean residuesPlow down old soybean residuesRotationRotation
Soybean cyst nematodeSoybean cyst nematodeSymptom/SignSymptom/Sign
Stunted yellow plants in patches or large Stunted yellow plants in patches or large areasareasPoorly developed rootsPoorly developed rootsSuppressed nodulationSuppressed nodulationLemon shaped cysts (females) on roots. Lemon shaped cysts (females) on roots.
Soybean Cyst NematodeSoybean Cyst Nematode
Soybean Cyst NematodeSoybean Cyst Nematode
Soybean cyst nematodeSoybean cyst nematodeControl MethodsControl Methods
Resistant varietiesResistant varietiesRotationRotation
Root knot nematodeRoot knot nematodeSymptom/SignSymptom/Sign
Stunted yellow plants Stunted yellow plants Knots (galls) on rootsKnots (galls) on roots
Root Knot NematodeRoot Knot Nematode
Root knot nematodeRoot knot nematodeControl MethodsControl Methods
Resistant varietyResistant varietyRotationRotation
Soybean mosaic (virus)Soybean mosaic (virus)Symptom/SignSymptom/Sign
Puckered leavesPuckered leavesMosaic pattern of yellow and green on leavesMosaic pattern of yellow and green on leavesBleeding Bleeding hilumhilum on infected seedon infected seed
Soybean Mosaic (virus)Soybean Mosaic (virus)
Soybean mosaic (virus)Soybean mosaic (virus)Conditions favoring developmentConditions favoring development
Seed borne diseaseSeed borne diseaseAphid transmittedAphid transmitted
Soybean mosaic (virus)Soybean mosaic (virus)Control MethodsControl Methods
Certified seedCertified seedResistant varietyResistant variety
Tobacco Tobacco RingspotRingspot Virus Virus Symptom/SignSymptom/Sign
Primarily Primarily seedborne seedborne at a low level in the at a low level in the fieldfieldThis results in scattered infected plants.This results in scattered infected plants.Maturity is delayed so they remain green Maturity is delayed so they remain green until killed by frostuntil killed by frostPods are underdeveloped, tops of plants Pods are underdeveloped, tops of plants have shortened internodes, and leaves are have shortened internodes, and leaves are distorteddistorted
Tobacco Tobacco RingspotRingspot
TobaccoTobacco RingspotRingspotConditions favoring developmentConditions favoring development
Nearby crops that may harbor the virusNearby crops that may harbor the virusInsect vectors are possible and disease is Insect vectors are possible and disease is often found near the edges of fields.often found near the edges of fields.Dagger nematode (Dagger nematode (XiphinemaXiphinema) may cause a ) may cause a low level of transmission.low level of transmission.
TobaccoTobacco RingspotRingspotControl MethodsControl Methods
Planting virus free seed.Planting virus free seed.
Wheat DiseasesWheat Diseases
Powdery Mildew (fungus)Powdery Mildew (fungus)Symptom/SignSymptom/Sign
Irregular shaped yellow areas on leaf Irregular shaped yellow areas on leaf initaillyinitaillyWhite powdery mass of fungus on upper White powdery mass of fungus on upper surface of lower leavessurface of lower leavesOlder PM colonies will have small brown to Older PM colonies will have small brown to black sexual fruiting structures present late black sexual fruiting structures present late in the springin the spring
Powdery MildewPowdery Mildew
Powdery Mildew (fungus)Powdery Mildew (fungus)Conditions favoring developmentConditions favoring development
Optimal powdery mildew development Optimal powdery mildew development occurs between 60occurs between 60-- 72 F basically cool, wet 72 F basically cool, wet conditionsconditionsHigh nitrogen fertilityHigh nitrogen fertilityDense stands of susceptible varietiesDense stands of susceptible varietiesHigh humidityHigh humidity
Powdery Mildew (fungus)Powdery Mildew (fungus)Control MethodsControl Methods
Resistant varietiesResistant varietiesRotation is of some value but limitedRotation is of some value but limitedBalanced fertilityBalanced fertilityFungicides (seed and/or foliar treatments) Fungicides (seed and/or foliar treatments)
Leaf rust (fungus)Leaf rust (fungus)Symptom/SignSymptom/Sign
OrangeOrange--red pustules mostly on upper leaf surfacesred pustules mostly on upper leaf surfacesRandomly scattered within the canopyRandomly scattered within the canopyUsually appears after headingUsually appears after heading
Leaf RustLeaf Rust
Leaf rust (fungus)Leaf rust (fungus)Conditions favoring developmentConditions favoring development
Temperatures from 59Temperatures from 59--72 F and free72 F and free--moisture. Needs adequate rainfall.moisture. Needs adequate rainfall.Overwinters far southOverwinters far southSpores carried by windSpores carried by wind
Leaf rust (fungus)Leaf rust (fungus)Control MethodsControl Methods
ResistanceResistanceFungicidesFungicides
Septoria Septoria leaf and leaf and glumeglume blotch (fungus)blotch (fungus)Septoria nodorumSeptoria nodorum
Symptom/SignSymptom/Sign
Elongate lensElongate lens--shaped lesions with yellow shaped lesions with yellow marginsmarginsBlack fruiting bodies in center of lesion help Black fruiting bodies in center of lesion help distinguish from tan spot. Often found in distinguish from tan spot. Often found in orderly rows.orderly rows.On the heads a brown to gray On the heads a brown to gray --brown brown discoloration occurs and discoloration occurs and pycnidia pycnidia are found are found on the infected glumeson the infected glumes
Septoria Leaf and Glume Blotch
SeptoriaSeptoria leaf andleaf and glumeglume blotch (fungus)blotch (fungus)Conditions favoring developmentConditions favoring development
Optimal development is between 68Optimal development is between 68--82 F 82 F wet, windy conditions.wet, windy conditions.Minimal wet periods of 6 hours, but mostly Minimal wet periods of 6 hours, but mostly needs 16 hours of wetness.needs 16 hours of wetness.
SeptoriaSeptoria leaf andleaf and glumeglume blotch (fungus)blotch (fungus)Control MethodsControl Methods
FungicidesFungicidesTillageTillage
Scab (fungus)Scab (fungus)Symptom/SignSymptom/Sign
Bleached Bleached spikeletsspikelets on part or all of wheat on part or all of wheat headheadPink or orange spore masses may be seen at Pink or orange spore masses may be seen at the base of infected the base of infected spikelets spikelets during periods during periods of high humidityof high humidityInfected heads are sterile or contain white Infected heads are sterile or contain white shriveled grainshriveled grainSame as Fusarium on corn (Same as Fusarium on corn (mycotoxinsmycotoxins))
ScabScab
Scab (fungus)Scab (fungus)Conditions favoring developmentConditions favoring development
Spores from corn, wheat and grass residue Spores from corn, wheat and grass residue spread to flowering wheat under warm, wet spread to flowering wheat under warm, wet conditions.conditions.Temperatures between 77Temperatures between 77--86 F and 86 F and continous continous moisture at flowering are most moisture at flowering are most favorable for epidemics.favorable for epidemics.
Scab (fungus)Scab (fungus)Control MethodsControl Methods
Tillage prior to plantingTillage prior to plantingRotation (limited value in areas with intense Rotation (limited value in areas with intense nono--till or reduced tillage corn production)till or reduced tillage corn production)No resistanceNo resistance
TakeTake--all (fungus)all (fungus)Symptom/SignSymptom/Sign
Infected plants are stunted and ripen prematurelyInfected plants are stunted and ripen prematurelyBest identified at heading by stunted growth in Best identified at heading by stunted growth in patches and heads are bleached white and often patches and heads are bleached white and often sterilesterileBlack lesions at base of crown under the lowest Black lesions at base of crown under the lowest leaf sheathleaf sheathPlants pull easily from the soil from extensive rot Plants pull easily from the soil from extensive rot rot.rot.
TakeTake--allall
TakeTake--allall
TakeTake--all (fungus)all (fungus)Conditions favoring developmentConditions favoring development
Continuous wheat productionContinuous wheat productionHigh pH, poorly drained soils or wet yearsHigh pH, poorly drained soils or wet years
TakeTake--all (fungus)all (fungus)Control MethodsControl Methods
RotationRotationMaintain good fertility levelsMaintain good fertility levelsNo good resistant varietiesNo good resistant varietiesControl grassy weeds before cropping to Control grassy weeds before cropping to wheat wheat
Barley yellow dwarf (virus)Barley yellow dwarf (virus)Symptom/SignSymptom/Sign
Ambiguous often look like nutritional Ambiguous often look like nutritional disordersdisordersFall infection results in patches of yellow, Fall infection results in patches of yellow, stunted plants. Spring infections usually stunted plants. Spring infections usually result in plants of varying heights and result in plants of varying heights and yellow or purple colored flag leaves after yellow or purple colored flag leaves after head emergencehead emergenceOccurs in patches of field where aphid Occurs in patches of field where aphid vectors feedvectors feed
Barley Yellow DwarfBarley Yellow Dwarf
Barley yellow dwarf (virus)Barley yellow dwarf (virus)Conditions favoring developmentConditions favoring development
Transmitted by aphidsTransmitted by aphidsCool, moist conditions (50Cool, moist conditions (50--65 F)65 F)Early planted fields attractive to aphidsEarly planted fields attractive to aphidsMild winter with aphidsMild winter with aphids
Barley yellow dwarf (virus)Barley yellow dwarf (virus)Control MethodsControl Methods
ToleranceToleranceLater planting dateLater planting dateControl aphidsControl aphids
Wheat spindle streak mosaic (virus)Wheat spindle streak mosaic (virus)Symptom/SignSymptom/Sign
NonNon--distinct yellow streaks can be confused with distinct yellow streaks can be confused with early stage powdery mildewearly stage powdery mildewOften produces yellowOften produces yellow--green mottling, dashes and green mottling, dashes and streaks. The streaks often have tapered ends streaks. The streaks often have tapered ends forming spindles.forming spindles.Entire field affectedEntire field affected----not patchy. Low spots in not patchy. Low spots in field can have more severe symptoms.field can have more severe symptoms.
Wheat Spindle StreakWheat Spindle Streak
Wheat spindle streak mosaic (virus)Wheat spindle streak mosaic (virus)Conditions favoring developmentConditions favoring development
Soil borne virusSoil borne virusTransmitted by fungus, in the fall.Transmitted by fungus, in the fall.Cool weather (46Cool weather (46--53 F) produces the most 53 F) produces the most symptomssymptoms“Disappears” as temperatures increase“Disappears” as temperatures increase
Wheat spindle streak (virus)Wheat spindle streak (virus)Control MethodsControl Methods
Resistant varietyResistant varietyRotation of some valueRotation of some valueLater plantingLater plantingPoultry manure may decrease disease Poultry manure may decrease disease incidenceincidence
Loose Smut (fungus)Loose Smut (fungus)Symptom/SignSymptom/Sign
Black smutted Black smutted heads on wheatheads on wheat
Loose Smut (fungus)Loose Smut (fungus)Control MethodsControl Methods
Fungicide seed treatmentFungicide seed treatmentPlant certified seedPlant certified seed
Alfalfa DiseasesAlfalfa Diseases
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Symptom/SignSymptom/Sign
Poor growthPoor growthWiltingWiltingBrown discoloration on stemBrown discoloration on stemRotted rootsRotted roots
Phytophthora Root RotPhytophthora Root Rot
Phytophthora Root RotPhytophthora Root Rot
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Conditions favoring developmentConditions favoring development
Cool, wet conditionsCool, wet conditionsPoorly drained soilsPoorly drained soils
Phytophthora root rot (fungus)Phytophthora root rot (fungus)Control MethodsControl Methods
Select well drained sitesSelect well drained sitesBreak up compacted soils to enhance drainageBreak up compacted soils to enhance drainagePlant resistance varietiesPlant resistance varietiesUse Apron seed treatments to avoid seedling Use Apron seed treatments to avoid seedling dampingdamping--offoff
Anthracnose (fungus)Anthracnose (fungus)Symptom/SignSymptom/Sign
Wilted stemsWilted stemsDiamond shaped lesions on lower stemDiamond shaped lesions on lower stemLesion gray with red marginLesion gray with red marginScattered in the fieldScattered in the fieldInfected stems with characteristic diamond Infected stems with characteristic diamond shaped lesion will also produce a typical shaped lesion will also produce a typical shepard’s shepard’s crookcrook
AnthracnoseAnthracnose
Anthracnose (fungus)Anthracnose (fungus)Conditions favoring developmentConditions favoring development
Warm, humid conditionsWarm, humid conditionsLate summer/ early fall weather can be very Late summer/ early fall weather can be very favorable for infectionfavorable for infection
Anthracnose (fungus)Anthracnose (fungus)Control MethodsControl Methods
Resistant varietyResistant varietyClean harvesting equipment before first Clean harvesting equipment before first cutting and when going from a known cutting and when going from a known infected fields to a healthy field.infected fields to a healthy field.
Sclerotinia Sclerotinia crown rot (fungus)crown rot (fungus)Symptom/SignSymptom/Sign
FallFall-- planted alfalfa dies in spring during planted alfalfa dies in spring during cool, wet conditions.cool, wet conditions.Cottony webCottony web--like growth on stems and like growth on stems and crownscrownsStems turn brown, then soft and mushy then Stems turn brown, then soft and mushy then disintegrate.disintegrate.Black fruiting bodies (Black fruiting bodies (SclerotiaSclerotia) on stem) on stem
Sclerotinia Sclerotinia Crown RotCrown Rot
SclerotiniaSclerotinia Crown RotCrown Rot
SclerotiniaSclerotinia crown rot (fungus)crown rot (fungus)Conditions favoring developmentConditions favoring development
Infection occurs in fallInfection occurs in fallPlants die in cool, wet springPlants die in cool, wet springFavored by late summer early fall plantingFavored by late summer early fall plantingPlanting into cloversPlanting into clovers
SclerotiniaSclerotinia crown rot (fungus)crown rot (fungus)Control MethodsControl Methods
Spring planting dateSpring planting dateDeep plowing to bury Deep plowing to bury sclerotiasclerotiaNo resistanceNo resistance
Leaf spots (fungus)Leaf spots (fungus)--Common Common LeptoLeptoSymptom/SignSymptom/Sign
Spots on leavesSpots on leavesNew growth most affectedNew growth most affected
Leaf SpotsLeaf Spots
Leaf spots (fungus)Leaf spots (fungus)--CommonCommon LeptoLeptoConditions favoring developmentConditions favoring development
Cool, moist seasonCool, moist season
Leaf spots (fungus)Leaf spots (fungus)--CommonCommon LeptoLeptoControl MethodsControl Methods
Early harvestEarly harvest
Spring Spring blackstem blackstem (fungus)(fungus)Symptom/SignSymptom/Sign
Black spots on lower leaves, petioles, stemsBlack spots on lower leaves, petioles, stemsEntire stem blackEntire stem black----first cutting problemfirst cutting problem
Spring Spring BlackstemBlackstem
SpringSpring blackstemblackstem (fungus)(fungus)Conditions favoring developmentConditions favoring development
Cool, moist early season and again in fallCool, moist early season and again in fallHeavy dew or rainHeavy dew or rain
SpringSpring blackstemblackstem (fungus)(fungus)Control MethodsControl Methods
Early cuttingEarly cuttingPlant moderately resistant cultivarsPlant moderately resistant cultivars
Verticillium Verticillium wilt (fungus)wilt (fungus)Symptom/SignSymptom/Sign
Scattered infected stemsScattered infected stemsEarly symptoms include VEarly symptoms include V--shaped shaped chlorosis chlorosis at leaflet tipsat leaflet tipsNot all stems on the same plant infected Not all stems on the same plant infected initiallyinitiallyInternal root tissue is often brown, but it is Internal root tissue is often brown, but it is not a dependable diagnostic feature.not a dependable diagnostic feature.
Verticillium Verticillium WiltWilt
VerticilliumVerticillium WiltWilt
VerticilliumVerticillium wilt (fungus) wilt (fungus) Conditions favoring developmentConditions favoring development
Introduced on seed usuallyIntroduced on seed usuallyCould be disseminated in manureCould be disseminated in manureInsects can can serve as vectorsInsects can can serve as vectorsCan spread within the field during cuttingCan spread within the field during cutting
VerticilliumVerticillium wilt (fungus) wilt (fungus)
Control MethodsControl Methods
Plant clean seed free of debrisPlant clean seed free of debrisPlant resistant varietiesPlant resistant varietiesDisinfestation Disinfestation of cutter bars and equipmentof cutter bars and equipment
Most Common Symptoms of Most Common Symptoms of Nematode InjuryNematode Injury
Field SymptomsField SymptomsStunting and sometimes yellowing of plants in Stunting and sometimes yellowing of plants in patches of varying sizepatches of varying sizeNot definitive, need to look at rootsNot definitive, need to look at roots
Plant Symptoms and SignsPlant Symptoms and SignsGalls, cysts, lesions or dead areas on rootsGalls, cysts, lesions or dead areas on roots
FUNGICIDE CLASSIFICATIONFUNGICIDE CLASSIFICATIONPROTECTANTPROTECTANT–– Forms a protective barrier on the plant surface that Forms a protective barrier on the plant surface that
prevents spore germination prevents spore germination egeg. . DithaneDithane, Bravo, , Bravo, thiramthiram
SYSTEMICSYSTEMIC–– Moves in the plant from point of application across the Moves in the plant from point of application across the
leaf or into new growth. Can move from roots to leaf or into new growth. Can move from roots to above ground parts. Prevents spores from germinating above ground parts. Prevents spores from germinating or kills them soon after germination.or kills them soon after germination. EgEg. Tilt, . Tilt, BaytanBaytan, , RaxilRaxil, , QuadrisQuadris, , RidomilRidomil..
ERADICATIVE (Curative)ERADICATIVE (Curative)-- kills fungus already kills fungus already present. Some systemic fungicides have some curative present. Some systemic fungicides have some curative activityactivity
TREATMENT THRESHOLDS FOR TREATMENT THRESHOLDS FOR FUNGICIDE APPLICATIONFUNGICIDE APPLICATION
Thresholds are available for making spray Thresholds are available for making spray decisions for wheat in the middecisions for wheat in the mid--Atlantic Atlantic region.region.Use stage of development and amount of Use stage of development and amount of disease present to determine need for an disease present to determine need for an application.application.
